I hate to say it, but there was homelessness in the 80s and it is only eclipse by our current state of homelessness.
https://www.coalitionforthehomeless.org/wp-content/uploads/2...
https://www.coalitionforthehomeless.org/wp-content/uploads/2...
Nobody was buying second apartments in NYC in the 80s. Nobody was buying apartments period. I knew people with brownstones for sale in spanish harlem that they couldn't get $10k for in the late 80s. 80% of _storefront_ space in midtown was vacant.
People buying vacation homes in Florida or Vermont aren't responsible for homelessness in major cities.